You should understand that the strength of dSLRs is in the Phase Detect Autofocus System, which is faster and more accurate than the alternative, which is Contrast Detection. Since PDAF is bigger, heavier and more expensive, so too are dSLRs. Cameras that only use CDAF may work fine for some things, but they can't work as well for all things. If you don't need those other things, then maybe a m4/3 is exactly what you do need. But for some things, it's a dSLR with PDAF, or nothing.